The finishing of stamped vehicle bumpers which, for example, are common to automobiles, trucks, tractors, buses and the like is very difficult, because of the wide variety of bumper curvatures. Vehicles are stylized to suit the manufacturer's requirements and hence bumpers for those particular vehicles have to fit with the stylized appearance. In view of there being so many different types of bumper shapes, it is difficult to build a single system which is capable of finishing all different types of bumpers. This has been a constant problem for bumper manufacturers which even to this day still rely to some extent on hand finishing of bumpers. Many attempts have been made in providing bumper polishing machines which move the finishing head in a variety of directions to achieve finishing or have in a line a variety of finishing heads positioned at various angles to finish the bumper as the bumper is passed in a single orientation through the line. It is common to use a variety of flap wheels and the like to finish the bumper surface in preparing it for final treatment, but due to varying bumper shapes, the abrading wheels wear quickly because there is sometimes lack of control and over pressure exerted on the abrading wheel.
A bumper finishing machine which is sensitive to various surfaces of the bumper is described in U.S. Pat. No. 3,593,464. The finishing head is mounted on a carriage which is capable of moving the bumper in various directions as the abrading head contacts the bumper. This system is provided to achieve as much versatility as possible with respect to the various positions in which the bumper may be supported while it is being refinished. Such system is inherently complex in nature and difficult to maintain in the difficult environment of the finishing area.
U.S. Pat. No. 2,166,461 describes the use of a cam system to vary the position of the article to be finished as it passes beneath the finishing heads which are located about a rotary table. U.S. Pat. No. 2,716,311 describes a centreless machine device which is capable of finishing the outside surface of the article where that surface is of irregular shape.
Accordingly, this invention overcomes a number of the above problems by providing a finishing system having one or more fixed rotary finishing heads where the bumper is guided past the finishing head in a controlled manner to polish the unique longitudinal curvature of the particular style of bumper.